Dendrobium amphigenyum Ridl., Trans. Linn. Soc. London, Bot. 9 (1916) 176.
Type: Kloss s.n. (Camp 6a, 3100 ft.) (holo BM).
An erect epiphytic or lithophytic herb. Pseudobulbs cylindrical or slightly dilated above, 5-8-noded below leaves, 7-40 by 0.4-0.8 cm, orange-yellow when dry, 2-3-leaved. Leaves coriaceous, suberect, lanceolate, acuminate, 5.5-12 by 1.2-2.5 cm. Inflorescences terminal, subterminal or from uppermost node below leaves, suberect, 6-8 cm long, few-flowered; bracts falcate, lanceolate, acute, 5-6 mm long. Flowers small, fleshy; pedicel and ovary 1.7-2.2 cm. Dorsal sepal elliptic, obtuse, 10-12 by 5-6 mm; lateral sepals very obliquely elliptic, obtuse, 9 by 9 mm; mentum subsaccate, 5-7 mm long. Petals falcate, oblanceolate, obtuse, 6 by 2 mm, with erose margins. Lip clawed, 3-lobed, strongly recurved at base, 0.7-0.8 by 0.7-1 cm; side-lobes erect, oblong-elliptic, rounded at apex, erose on margins; midlobe smaller than side-lobes, deeply emarginate with a mucro in the sinus, with each lobule acute or subacute; callus fleshy, 3-ridged with a lower rugulose apex. Column 2 mm long; foot incurved, 5-7 mm long.
(after Cribb, 1983).
Colours: Sepals and petals creamy to green, mottled with purple; lip purplish.
Habitat: Epiphyte in mossy forest. Also found as a terrestrial on road banks. Altitude 1600-2300 m.
Flowering time in the wild: February, May, June, August, December.
Distribution: New Guinea.
Distribution in New Guinea: Papua (Paniai and Jayapura Regencies); Papua New Guinea (Enga, Eastern Highlands, Madang, and Morobe Provinces).
Map: AMPHIMAP.JPG [Dendrobium amphigenyum Ridl., distribution map, redrawn from P. Cribb, Kew Bull. 38 (1983) 285, map 6, with new records added.]
Notes: Dendrobium amphigenyum has been confused in the past with both Dendrobium dendrocolloides and Dendrobium woodsii. It differs from the former in having a three-lobed lip in which the midlobe is as long as the side-lobes and is deeply emarginate. From the latter, it may be distinguished by its shorter midlobe in which the lobules are tapering and acute rather than dilated and obtuse above.
(after Cribb, 1983).
Cultivation: Cool growing epiphyte.